What does OSPF use to calculate the cost to a
destination network?
bandwidth
bandwidth and hop count
bandwidth and reliability
bandwidth, load, and
reliablity
2
Which of the following should be considered when
troubleshooting a problem with the establishment of neighbor
relationships between OSPF routers? (Choose three.)
OSPF interval timers mismatch
gateway of last resort not
redistributed
interface network type
mismatch
no loopback interface
configured
administrative distance
mismatch
inconsistent authentication
configuration
3
Which router is the root of an SPF tree?
border router
nearest neighboring router
local router
trunk router, as determined by the
SPF algorithm
4
In which types of networks are OSPF DR elections
necessary? (Choose two.)
point-to-point
point-to-multipoint
broadcast multiaccess
nonbroadcast
multiaccess
5
What will be the result of the DR and BDR elections
for this single area OSPF network? (Choose three.)
HQ will be DR for
10.4.0.0/16.
Router A will be DR for
10.4.0.0/16.
HQ will be BDR for
10.4.0.0/16.
Router A will be DR for
10.5.0.0/16.
Remote will be DR for
10.5.0.0/16.
Remote will be BDR for
10.5.0.0/16.
6
Refer to the network shown in the diagram. Which
command sequence on RouterB will redistribute a Gateway of Last
Resort to the other routers in OSPF area 0?
RouterB(config)# ip route
0.0.0.0 0.0.0.0 172.16.6.6
RouterB(config)# ip
default-route 0.0.0.0 0.0.0.0 172.16.6.6
RouterB(config)# router ospf 10
RouterB(config-router)# redistribute ip
default-route
7
Why is it difficult for routing loops to occur in
networks that use link-state routing?
Each router builds a simple view of
the network based on hop count.
Routers flood the network with LSAs
to discover routing loops.
Each router builds a complete and
synchronized view of the network.
Routers use hold-down timers to
prevent routing loops.
8
What information can be obtained from the output of
the show ip ospf interface command? (Choose three.)
link-state age intervals
timer intervals
router ID number
link-state update intervals
neighbor
adjacencies
9
RouterA, RouterB, and RouterC in the diagram are
running OSPF on their Ethernet interfaces. Loopback interfaces (Lo
0) are configured as shown. What happens when RouterD is added to
the network?
RouterB takes over as DR and
RouterD becomes the BDR.
RouterD becomes the BDR and RouterA
remains the DR.
RouterD becomes the DR and RouterA
becomes the BDR.
RouterC acts as the DR until the
election process is complete.
RouterD becomes the DR and RouterB
remains the BDR.
There is no change in the DR or BDR
until either current DR or BDR goes
down.
10
What are the benefits of the hierarchical design
approach that is used in large OSPF networks? (Choose
three.)
reduction of routing overhead
increased routing overhead
faster convergence
slower convergence
distribution of network instability
to all areas of the network
isolation of network instability to
one area of the network
11
Which command sequence will enable OSPF in the
backbone area for the two Ethernet links on RouterA?
RouterA(config)# router ospf
1
RouterA(config-router)# network 172.16.4.0 0.0.1.255
area 1
RouterA(config)# router ospf
10
RouterA(config-router)# network 172.16.4.0 0.0.0.255
area 0
RouterA(config-router)# network 172.16.5.0
0.0.0.255 area 0
RouterA(config)# router ospf
10
RouterA(config-router)# area 0 network 172.16.4.0
0.0.1.255
RouterA(config)# router ospf
0
RouterA(config-route)# network 172.16.4.0 0.0.255.255
area 0
Link-state hello updates can cause
broadcast flooding.
Link-state protocols place
significant demands on router processors and memory resources.
Link-state protocols require a
knowledgeable network administrator.
Link-state protocols do not support
Variable Length Subnet Masking.
13
What speeds up convergence in a network using
link-state routing?
updates triggered by network
changes
updates sent at regular
intervals
updates sent only to directly
connected neighbors
updates that include complete
routing tables
14
Because of security concerns, a network administrator
wants to set up authentication between two routers. Which of the
following commands will configure Router_A to trust Router_B with a
clear text password of apollo?
Router_A(config-if)# ospf
authentication-key apollo
Router_A(config-if)# ip
authentication-key apollo
Router_A(config-if)# ip ospf
authentication apollo
Router_A(config-if)# ip ospf
authentication-key apollo
15
How can the OSPF cost for a link be established?
(Choose two.)
It is set to 1544 by default for
all OSPF interfaces.
It can be set with the ip ospf
cost command.
The configured loopback addresses
map to link costs.
It is calculated proportionally to
observed throughput capacity of the router.
It may be calculated using the
formula 108/bandwidth.
16
A network administrator has configured a default route
on Router_A but it is not being shared with adjacent Router_B and
the other routers in the OSPF area. Which command will save the
administrator the time and trouble of configuring this default route
on Router_B and all of the other routers in the OSPF area?
The routers in the diagram are configured as shown.
The loopback interface on router R1 is labeled as lo0. All
OSPF priorities are set to the default except for Ethernet0 of
router R2, which has an OSPF priority of 2. What will be the result
of the OSPF DR/BDR elections on the 192.1.1.0 network? (Choose
two.)
R1 will be the DR
R1 will be the BDR
R2 will be the DR
R2 will be the BDR
R3 will be the DR
R3 will be the
BDR
18
Which router command will display the interface
priority value and other key information for the OSPF configuration
of the serial 0 interface?
router# show ospf serial
0
router# show interface serial 0
OSPF
router# show ip interface serial
0
router# show ip ospf interface
serial 0
19
Which of the following are required when adding a
network to the OSPF routing process configuration? (Choose
three.)
network address
loopback address
autonomous system number
subnet mask
wildcard mask
area
ID
20
What does OSPF use to reduce the number of exchanges
of routing information in networks where large numbers of neighbors
are present? (Choose two.)
